Fishing is one of the oldest vocations and avocations. In the last fifty years or so the equipment and fishing techniques have evolved into increasingly sophisticated products and strategies for catching fish. Bait fish seek water at a certain temperature and water depth. The big fish follow them to feed on them. Numerous electronic devices have been provided to detect water temperature variations at different depths, to locate schools of fish at different locations and to provide a read-out of underwater topography where fish congregate. Modern trolling motors allow both large and small fishing and commercial boats to move at slow and controlled trolling speeds through the water.
It is preferred to equip trolling boats with the ability to fish with more than one fishing rod at a time in order to multiply the number of possibilities for catching fish simultaneously or in close sequence to thereby increase the chances of catching fish. Fishing boats are often equipped with mounting tracks along their port and starboard gunnels and across the transom top board to thereby enable fishermen to use more than one fishing rod, because many rod holders will fit into the track. Usually the track is mounted to the boat permanently.
Down riggers add another dimension to trolling fishing by allowing fishermen to fish at a controlled depth. Being able to fish with more than one down rigger at a time is another strategy that increases the chances of catching fish. Down riggers have a long boom with a heavy-duty aircraft cable line to which a heavy sinker is attached. The heavy-duty line and sinker are necessary to keep the fishing line at a controlled or constant depth at trolling speeds. To maximize the performance of down rigger, they need to be mounted on a swivel mechanism that is easy to swivel and easy to lock and unlock. With multiple down riggers deployed it is necessary to be able to adjust the down rigger masts by swiveling them so that their lines will not interfere with each other. In addition, as the boat navigates a turn in its course, being able to swivel down riggers helps keeps the fishing lines from fouling the propellers. Other and different fishing techniques, such as planer board fishing, are also enhanced by mounting the associated rods on swivel bases.
Although hitherto a variety of different types of swivel bases for mounting down rigger masts and planer board masts have been provided in an attempt to accommodate most, if not all, of the aforementioned usage parameters, there remains much room for improvement in such devices. For example, there is a need to improve the ease of which the swivel base can be locked and unlocked to permit the desired swivel action. There is also a need for improvement in the locking system provided in the adjustable swivel base from the standpoint of strength, elimination of play or “slop” in the various locked positions of the device, reduction in manufacturing costs, and ability to smoothly operate under heavy applied loads that are exerted by the cantilever action of the down rigger and planer board masts on the mounting base.
With all these needs, there still remains an overall need that such particular needs be met with an improved adjustable swivel base mechanism able to take the extreme loads of big fish and heavy sinkers on the fishing lines even when trolling at relatively fast deep sea sport and commercial fishing speeds.